1923-cnoronha

A N E W S P E C I E S O F OCHTHEPHILA FROM PORTO SANTO

BY A. C. NORONHA. -

(Read before ihe sociery. Ma,, 5th. rg23).

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POKTOSANTO,one of the Madeira Islands, is a plnce very well known t o coiichologists for its numerous endemic forms, and though many investigators Iiave brought t o liglit its highly iiiteresting inalacological fauna, there still remaiii a few species wliicli hitherto Iiave not been kuown. I t is one of these specific forms we propose to deal witli here. Ochthephila cockerellii, nov. sp. Testa umhiiiinta di~coideasen conr~ioideo-dep~esra, solidula, levilef. striata et denrc grnnztfata; spira uix seu pnruni elevata, apice ncufi~~scula serc óreriifer rotiindata ;sutura iriipress<~ ;nizf~actus8 convcxiz~sculi;r~lfimus sublimbafo-cari~iailli, antice parum deflexus, óasi convexus; umbiiicus patulur, spirniis, i~lfundi6ui~rr>iis, n n f ~ a c t u penirlti~~~o . fere clausus ;apertrira obliqrra, e l l i ~ t i i o ~ rofundata;pcrisfol>ia simpiex 7uargiliibt~siilterrr~ptis,caifojundis, supero recto, basali sinun fo, a d umdilicurx 7-eflexli~scuiu. »iam. maj. 19, min. 1 7 , alt. 7-12 mm. Tiie present sprcies evidently belongs to the subgenus Teclula established I>y Lowe for a smali group of four species of which one, 0. lyelliana (I.owe), is peculiar to the Desertas Islands, whilst the three others 0. afúersii (Loive), 0. bulwerii (\Vood) and 0. tectifo~~~rir (Sow.) are only to bc met mith at Porto Santo and its adjacent islets. Like 0. albersii and 0. bulwerii, 0. cocke~elfiiisaconriiied tO ihe main island and tias been found only in a subfossil condition, not rarelg, by Mr. José J. d e Sousa and myself in tlie eartiien deposits along the seasliore, t o the eastward of tlie tovn, from Cabeco d o Vaie d o Touro as far as Penedo and its vicinity. 'l'liese deposits lie on a raised heacli of pleistocenic oi-igin, and they may be perliaps of the same epocli as the tieach on which they rest. They are often formed of somewhat loose eartti and broken pebbles, which came down from t h e hills above, and in this stuff many species of l a n d ~ shells may be found enibedded. the other three species of Tectula have Apart from 0. tectz~o~~riiq much in common irith the present one. T h e nearest ally of 0. cockevellii iis manifestly 0. albersii, from whicli, liowever, it differs by its larger size, more open umbiiicus and conspicuous granulations, especially at ttie base.

85

X O X O \ ~ I ~:A OCHTHRFI
~ ~ o t i rSANTO. o

I t is one of the largest memhers of tlie section Teciuia, and it certainiy displays tviro well separated varieties. O n e of these, \\,liich nze consider as tlie normal state, is very depressed, thin, witli very low conical spirc, acute at tlie apex, the base rather round; the other, nained here ixflata, is mucli liigher, more solid, with the spire slightly routided, the n,horls subgibbous, the apex rather obtuse and tlie base more convex. Comparing tliese tive states wit11 0. aibenii, the latler combines the not too niuch inflated base of the normal phasis with the somewhat arcuated spire of in/íirfa, which is far íroiii being dome~shaped as is tlie case witli 0. ázdi7uerii. At tlie same time, the aperiure, not very much deflected nnd slightly angulated in the middle: and the shai-p keel not doi~iiwardlypruduced, are conspicuous feaiures that the two varieties have'in common with 0. albersii. Now, if we compare the actual species with 0. testudinalir (Lowe), though the latter lias been included by I.onw in the section D i r ~ u i c , \.e fiiid some features commoti t o lhe two species. They are of a

Iarge and seiisii>ly q u a l size, and have botli ai1 infundii>uliform uiiibilicus, 0. tesf7tdi7znZir conibining aiways the depressed spire of O. coikereiiii not>iialis with tlie tumid base of inflata. Riit the ultimate ,.vtiorl of 0. tcrtudinalis, which is far from having a produced keel, its subpapillate apex, its recurved peristome, witli a very thin iamina connecting tlie two niargins, its faint granulations, certainly separate it specifically from the present forni. 0. iochereilii was appartntly adorned above 154th a narroiv median fascia, whilst the iinder one 1i.a~uni- or bi~fasciated,and niang stili shom a sliininy appearance, parlicularly a t the base. I\'ithout venturitig far into geiiealogical speculation, we may perhaps estahlish that 0. cockerellii is, througli its tivo phases, a sort of liiik betiv<:eii 0. festudinalir on one side aiid 0. alúcrrii on the oiiier, ivliilst the latter is again a link betiveeii 0. rorkerclliiand 0. úu/?uerii. Some autbors, as d e Paiva and l\'ollaston, state tiiat they Iiavc met with subfossilized exaniples of 0.festudinaiis, tlie foslirer in a locality at the east of Porto Santo, atid tiiç latter in the south, ar

JOURNAI. O F

CONCHOLOGY,

VOL. 17,

'VO. 3, IIIICEMBGR, 1923

86

Campo de Baixo. De Paiva says about that species: "Fossilis, carina exsertiore, ad Zimbral da Areia rarissima." Perchaiice would not the specin~ensof this locality be the true 0. cockerellii, the appearance of this çpecies leading him to take it for 0. ierfudinaiis? I n the collection of the Funchal Seminary there are two specimens of 0. cockerellii labelled as 0. testudinaiis, and this fact reinforces our suspicions t h a t there has always been confusion about the two species, and that 0. testadinaiis iiiust be, perhaps, considered as a quite recent one, localised in a restricted area, in the north of Porto Santo. It has been said also tliat tliere are no intermediate fornis hetween O. albeirii and O. I ~ ~ l ~ u e rhut i i , we possess some examples in our ccllection tliat we do not know where to place. They were taken on tlie median slopes of Pico do Facho, ahove the trachitic ridge of Portelinha de Nossa Senhora, the only spots where the two species live mixed together, and to x7liich 3. IiuiwerK at least well cliaracterised, seems to he confined. We have pleasure in naming iliis species alter Prof. T. D. A. Cockerell, of Colorado University, to \~.liose kindness ive are very much ~ndebted.