18 



AUGUST BRINKMANN. 



[REP. OF THE "MICHAEL SARS" NORTH 



The shape agrees well enough with Joubin's con- 

 tour figure; here also the tentacles are seen to project, 

 not from the foremost curvature edge of the head, but 

 from its sides. The shortness of the tentacles is due to 

 contraction. 



With regard to the anatomical structure, the fol- 

 lowing features may be specially mentioned: 



The muscle layers of the body wall are reduced, 

 the maximal thickness of the longitudinal layers being 

 only 35 ,«. 



The stomach and pyloric tube are extremely short, 

 the point of transition between them lying beneath the 

 brain. The intestine shows 22 pairs of large diverticula, 

 placed — in contrast to all other known species of the 

 genus 1 ) — at considerable intervals, as in the case of 

 Pelagonemertes. They are furnished with some few short 

 pouches but exhibit no other trace of ramification. The 

 same applies to the pair of large diverticula on the 

 intestinal caecum. 



The structure of the tentacles is the same as in 

 B. chuni Burger (6), and the same applies to the pro- 

 boscis, which has 17 — 18 proboscideal nerves. 



The lateral muscles following the nerve stems are 

 here, in contrast to the mentioned species, only very 

 slightly developed. 



The proboscis sheath is considerably longer than in 

 B. chuni, without however, extending out into the point 

 of the tail. 



The dorso-median vessel terminates slightly in rear 

 of the point where it enters the rhyncocoelomic cavity. 



The specimen in question is a $ with 7 pairs of 

 ovaries developed, the apertures lying on the inner side 

 of the lateral nerve stems. Only one egg is matured in 

 each ovary. 



Habitat: Joubin's type specimen was taken in the 

 North Atlantic. (Lat. 36° 17' N; long. 28° 53' W) in a 

 vertical haul 3000 — metres. The specimen from the 

 "Michael Sars" was taken at St. 84 (Lat. 48° 04' N; long. 

 32° 25' W) 13 , 7 at 2000 metres depth (3000 metres of wire). 



Balsenanemertes Hjorti n. sp. 



As regards external habitus, this species follows in 

 nearly all essentials the species, hitherto known with an 

 exception however, in the case of the tentacles, which 



are here only apparent as short points, despite the fact 

 that the specimen in question was fully mature. 



In contrast to B. chuni and B. lobata, the intestinal 

 caecum is furnished with two pairs of diverticula. The 

 intestinal diverticula are clearly divided into a dorsal and 

 a ventral main branch, between which are found the 

 lateral nerve and vessel. As a specific character may 

 be further noted the development of a thick muscle 

 layer extending from the insertion of the proboscis down 

 between the proboscis sheath and the ventral cerebral 

 commissure. 



The specimen in question is a male, with 7 — 8 

 testicles, spherical in form, and containing fully developed 

 spermatozoa. 



Habitat: St. 92 (Lat. 48° 29' N; long. 13° 55' W). 

 - 3 h, at 1000 metres depth, (1500 metres of wire out). 



Balaenanemertes lata n. sp. 



This species also is known in but a single specimen. 

 And indeed, as regards the smaller species of pelagic 

 nemerteans generally, the number of specimens in the 

 material of the expedition is remarkably small; with the 

 unusually large catches made, however, it is reasonable to 

 suppose that some might have escaped observation. 



The species closely resembles B. Hjorti, not only in 

 the slight degree of development of the tentacles, but also 

 as regards the intestinal caecum, which here also is furnished 

 with two pairs of diverticula, though these are here 

 considerably more developed, and with a not inconsider- 

 able degree of ramification. It may be distinguished 

 from the foregoing species by the entire lack of muscula- 

 ture between the proboscis sheath and the ventral cere- 

 bral commissure, as also by an altogether extreme devel- 

 opment of the muscles extending from the insertion of 

 the proboscis to the dorsal and latero-ventral parts of the 

 body wall. 



The testicles are elongated, almost sausage-shaped, 

 some of them opening on the under side of the head. 1 ) 



Habitat: St. 84 (Lat. 48° 04' N; long. 32° 25' W). 

 15 /7, abt. 1333 metres depth, (2000 metres of wire out). 



J ) Only three are mentioned in this report; to these must be 

 added four new species in the rest of the material I have had to 

 work upon. 



. ') It should be noted that the various species of the genus 

 Balcenanemertes are most intimately related one to another, so much 

 so that only a detailed and richly illustrated description — such as that 

 given in the monograph by the present writer, referred to in the 

 introduction — will be of any use for purposes of absolutely certain 

 identification. 



