46 WESLEY R. COE. 



between the nemerteans with and those without tentacular 

 appendages. This species, Bal&nanemertes chuni, was taken in 

 the Indian Ocean, in a region where the depth of water was 2,500 

 meters. This specimen, although a sexually mature male with 

 cephalic gonads, was provided with a pair of short sickle-shaped 

 lateral processes, or papillae (Fig. 10, /) closely resembling the 

 rudimentary tentacles in the young individuals of Nectonemertes 

 mirabilis. It is by no means certain, however, that these pro- 

 cesses might not have developed into longer tentacles if the 

 individual had lived until the spermatozoa were quite ready to 

 be discharged. They would doubtless have been much more 

 conspicuous in life than they appear in the preserved specimen, 

 for the tentacles of Nectonemertes are such highly distensible 

 organs that they suffer enormous contraction upon preservation, 

 as is indicated in figures 18 and 19. 



There are five pairs of spermaries in this species. These are 

 situated immediately behind the brain. Each gonad opens by a 

 short sperm duct which leads to the summit of a blunt or rounded 

 papilla (Fig. 10, sp) on the lateral border of the head. Female 

 is still unknown. 



3. Bathynectes. \nBathynectes murrayi Brinkmann ('12) finds 

 a remarkable modification of the reproductive organs in the male. 

 In this bathypelagic nemertean from the North Atlantic the 

 spermaries are provided with muscular walls as in Nectonemertes, 

 and the sperm ducts, instead of ending in minute papillae on 

 the surface of the head as in all other species, are prolonged in 

 some individuals into slender muscular penes (Figs. 15, 16, pe). 



There are from five to seven pairs of these organs on the 

 ventral side of the head, corresponding to the same number of 

 cephalic spermaries (Figs. 15, 16). That the penis is actually 

 an outgrowth from the body walls is shown by the fact that its 

 walls, like those of the body, consist of basement layer and 

 circular and longitudinal musculatures. The organ is evidently 

 capable of muscular contraction and may be considered a true 

 copulatory organ. 



In several of the specimens collected the penes were torn 

 from their insertions in the body walls, and Brinkmann offers 

 the suggestion that they may have been inserted into the ovaries 

 of the females and held there to serve as spermatophores. 



