10 



E. ARNESLN. 



[REP. OF THE "MICHAEL SARS" NORTH 



giilarly scattered and of variale size. No trace of skin or 

 other soft parts is left — only a pumice-like dictyonal 

 framework exhibiting an irregular meshwork of confused 

 strong hexacts with a prickly surface and provided with 

 rather robust pegs. The thickness of the wall is 1 — 2 

 mm., and there seems to be no noteworthy differences 

 between the dermal and the gastral surfaces. 



Geographical distribution. Of this genus 5 spe- 

 cies have been described from the Pacific (Ch. lamella 

 Schulze, Ch. hamatum Schulze, Ch. doederteinii Schulze, 

 Ch. calyx Schulze (26 p. 320—326.) and Ch. tenerum 

 Schulze (29 p. 81). 



From the Atlantic only 2 established species are 

 known Ch, Schulzei Topsent (34 p. 33) and Ch. ijimai 

 Topsent (41 p. 53) dredged by the "Hirondelle" and 

 "Princesse Alice" off the Azores at depths between 861 — 

 1919 m. — The "Caudan" specimen from the Gulf of 

 Gascogny (1710 m.) and the specimens recorded from the 

 West Indies, Bermudas and off the coast of Portugal being 

 all but -small undetermined fragments. 



The Cho/ielasma from the "Michael Sars" expedi- 

 tion was obtained at the trawling station 10 (Lat. 45" 

 26' N., Long, 9 U 20' W.) during the cruise from Plymouth 

 to Gibralter at the entrance to the Bay of Biscay at a 

 depth of 4 700 m. on a bottom of globigerina ooze. 



This specimen cannot with certainty be referred to 

 any distinct species, as the parts on which the specific 

 characters are based are absent, but it may perhaps be 

 identical with Ch. Schulzei Topsent, as this species 

 according to Topsent (41 p. 51) seems to be rather com- 

 mon among the Azores and perhaps occurs also off the 

 coast of Portugal — the undetermined fragments recorded 

 from that locality by the "Challenger" exhibiting at least, 

 according to the same author, a close affinity to Ch. Schulzei. 



Aphrocallistes beatrix J. E. Gray sensu F. E. Schulze. 



PI. I, fig. 5, 6. 



Vide Litter: 30 p. 144. 



St. 23. Several specimens. 



At this station several pieces of Aphrocallistes were 

 taken, but only abraded diactinal skeletons or mere frag- 

 ments of skeletons, so that it has been difficult to deter- 

 mine the species. Of this genus six species have been 

 described, but according to Schulze (30) they are all 

 referable to two species appearing under different aspects 

 "wie etwa die Tarrus-, Nardorus- and Auloplegma-Form 

 irgend einer Kalkschwammspecies" (op. cit. p. 147). The 

 two species regarded as main types are Aphrocallistes 

 beatrix .). E. G r a y and Aphrocallistes vastus F. E. Schulze. 

 The others Aphr. bocagei Perc. Wright, Aphr. ramosus 

 F. E. Schulze and Aphr. azoricus Topsent, are to be regarded 

 as three different aspects of Aphr. beatrix, while Aphr. 



whiteavesianus Lambe is to be regarded as belonging to 

 Aphr. vastus F. E. Schulze. 



Aphr. vastus with its by-form belongs to the Pacific 

 [Aphr. vastus from Japan, 329 m. (26, p. 317) and Aphr. 

 whiteavesianus from Vanconver 730 m.]. The other, 

 Aphrocallistes beatrix, has been recorded both from the 

 Indian Ocean, the Atlantic and the Pacific. 



The type species is known only from the Indian 

 Ocean [Malacca, Bombay and the Andaman 28], the 

 ramosus-iorm*) from the Pacific (26, p. 319) and the 

 azoricus-loxm from the Atlantic (41, p. 48), while the 

 bocagei-form, has a wide range both in the Atlantic [W. 

 Ireland, Coast of Spain, Portugal, France, Cape Verde, 

 Azores, W. Indies etc., between 500 — 1300 m.], in the 

 Indian Ocean and in the Pacific. 



To judge from the geographical data, above mentioned 

 and from the external appearance of the skeletons the 

 "Michael Sars" specimens most likely belong to the 

 species beatrix J. E. Gray sensu Schulzei. 



The main type most surely is not present, only the 

 bocagei-lorm, nearly all the specimens exhibiting the 

 ordinary habit of that form, a tube gradually widening 

 upwards with numerous radial finger-like swellings on the 

 lateral walls "and the axis of the tube exhibiting as a 

 rule a slight curvature" (like those figured 26, fig. 1, 

 pi. LXXXIII, and 30, fig. 6, pi. XIV). Sometimes there 

 are two parallel tubes the lateral swellings of which ana- 

 stomose. The structure of the diactinal framework corre- 

 sponds with Schulze's description (p. 314,26). In most 

 specimens sieve-septa, like those figured in op. cit., pi. 

 LXXXIII, fig. 2 often in several stages are present. A ter- 

 minal sieve-plate has not been observed as all the upper 

 parts have visibly been broken of. 



In some specimens there are small patches with loose 

 spicules still preserved at the base of the finger-like out- 

 growths, showing a striking resemblance to the spiculation 

 in the ramosus-form. 



As the ramosus-form has only been recorded from 

 the Pacific, the "Michael Sars"'s locality would incase 

 furnish a noteworthy extension of its distribution, the 

 specimens having been obtained from the Spanish Bay 

 (lat. 35" 32' N, long. 7" T W) at a depth of 1215 m. 



Hyalonema Gray. 



Of this genus the „Michael Sars" obtained 8 spe- 

 cimens from stations 10, 23, 35 and 53. 



But nearly all the specimens are in a more or less 

 bad condition, and therefore very difficult to identify. 



') The form obtained off the Azores and determined by Top- 

 sent as Aphrocallistes ramosus Schulze 34 the autor has later 41 

 recognized as Aplirocallistes azoricus Topsent. 



