332 



SCIENCE-GOSSIP. 



more cr less local, and the birds return, no 

 doubt, to their regular hamtts in a fev.- hours' 

 time. They are, moreover, chiefly observed in 

 the autumn. 



■'Gj'.es. — One effect of gales has already been 

 alluded to, namely, that they arrest or make 

 impossible the migratory movements. At sea, 

 however, they have a direct influence on the 

 migrations of certain marine species, such as skuas, 

 phalaropes, petrels, etc. These birds in the 

 autumn are occasionally driven out of their course 

 by severe gales, and appear on our coasts in 

 exceptional numbers. 



"Fog. — It often happens that during an important 

 migratory movement in the autumn or winter, fog 

 prevails. On such occasions more birds than usual 

 approach the lanterns of the light-stations and are 

 Mlled, sometimes in considerable numbers, by 

 striking Eeslnst the glass. This phenomenon is 

 ar::.ier rf:e:: ;f those anticy clonic spells which 

 Jiave c~- — 5-::oned as favourable to and causing 



emigration, and it is thus not surprising that the 

 birds should encounter foggy weather during their 

 movements. Such atmospheric conditions are well- 

 known to meteorologists to be characteristic of 

 these high-pressure systems, and of their frosty 

 periods, which latter are also the chief cause of the 

 winter mo%'ement3. There is also some direct 

 evidence that birds lose themselves in foggy weather, 

 since practically non-migratory species, such as 

 sparrows, appear during its prevalence at unusual 

 seasons at stations just off the coast." 



Although it has been necessary to quote largely 

 from the foregoing report, still the fringe, as it 

 were, of the subject only has been reached. So 

 much more valuable information will be found 

 there that no person interested in bird migration 

 should fail to read the whole, and attentively study 

 the conclusions arrived at by the committee. 



ARMATURE OF HELICOID LAXDSHELLS. 



V\"iTH A Nev,- Species of Plectofylis. 



By G. K. Gude, F.Z.S. 



'Continued from page soi.) 



pLECTOPYLlS daihratuloides Q) (fig. ±A^-i)- 

 ■^ Colonel Beddome has kindly lent me for 

 examination a number of shells of Plectopylis, from 

 the AnamuUay Hills, which appear to be unde- 



Fig. ^.—Plsr.zpyli- dathratuloidii. 



scribed, and for which I adopt the name oi Plectopylis 

 claihraMoides, suggested by Colonel Beddome. It is 

 possible, however, that this form already exists in 

 some collections under the name of P. dathratvla ; 

 for, as already mentioned in discussing that species, 

 I beUeve the specimens referred to under that name 



f^) PUctopylis claihratuloides. n^sp. — Shell depressed coni- 

 cal, modera-t^ly v.T^'b'^icated, pale corneous, translncent, finely 

 sf^- rer^ ir ; ; ;:5.ted by raised ribs above, finely and 

 C-ise.j r;: :r - = r. i a little shining below ; whoris 5§, slowly 

 i'zriii\-z £;;-;;.- convex, sntore impressed. Periphery 

 ~;:" i" =:::e :;:r.7r;5sed keel, above which revolve 2 

 raise- -z.Th. z-.izii. :-e lower provided with a firinge of 

 .---"-- --''-\~-- /■-r=:":-"5 s-t-.-adrate; peristome simple, a 

 -•• i ;;::^t-ei. -zz-z[.\z-l^ deep and moderately "wide. 

 -'-'-i'-i- =m=r.;re ;-e ;-.r:-£ -.trtical, simple plate. Palatal 

 ar— = -.ure :z :~; seri^; -Z'-ir series with one jxjsterior, 

 -.5:-.;:l. ::-::=.- ;:;:i ar.i ;-; — i-u:e anterior denude : 

 -C tr a-. a ^--- '-'-i zii.ir-.z . er-ical tooth and a small 

 s.-:er:;r zi.-:::-e :r. am:;;- ;-; tlt-^aied horizontal fold 

 £= -j^ :-i '-~z:..za.. ar.ru.s.:;;- a-; a sna". fold above the 

 -.'■ -"-•■^- ^" r-:;?'-'' • -i; ^- -i— 5:er f ~;llimetres : minor 

 ■^^^^^-^s^-, i 5 ~ -.-- ' - ~ e>r&s ; asis. 55 ~ : . ': — eir&s. — Habitat..\na- 

 muilay Hilis, India.— Type in Colonel Beddome's collection. 



in Mr. Nevill's Hand List as from Sikkim belong to 

 this ne'.v form. Plectopylis clathratuloldes differs from 

 P. claihi-aiida in being more elevated, in having a 

 narrower umbilicus, and in being less shining and 

 more tumid below, while it differs from P. reiifira, 

 in being less elevated and in having a wdder 

 timbilicus ; it is, in fact, intermediate betv,-een those 

 two species. The parietal armature consists of a 

 simple, strong, vertical plate, which is not notched, 

 and is without supports (see fig. AAi). The palatal 

 armature is in two series, the first (upper) series 

 consisting of a posterior vertical tooth and a 

 minute anterior denticle ; the second (lower) series 

 being composed of a posterior vertical tooth and a 

 small anterior denticle ; below the umbilical angula- 

 tion there is, besides, an elongated horizontal fold, 

 and above the peripherial angulation a small fold (see 

 fig. 44^, which shows the base of the shell with the 

 palatal armature visible through the shell- wall). 

 The specimen figured is one of the Anamullay 

 HiUs specimens belonging to Colonel Beddome's 

 collection. SLx specimens from Madura, India, 

 also in Colonel Beddome's collection, I refer to 

 this new form ; four of these are immature and 

 exhibit two sets of armatures, as is the case in 

 immattire specimens of P. retifera. 



Mr. E. R. Sykes and others have drawn my 

 attention to the fact that the name Austenja, pro- 

 posed by me for a section of Plectopylis (atite p. 300) 

 is preoccupied. Under these circumstances it is 

 necessary to re-name the section, and I therefore 

 propose the name Syhesia, in honour of Mr. Sykes, 

 who was the first to point out this fact. 



