87 



about the digestive tract tliis author notes'), at the right side of the stomach, "un cor])s dur 

 et jaunatre", the function of which he could not malce out. Pelseneer ") declared this hard 

 body to be the muciparous gland. I too have found it in all specimens; in formol-preservation 

 it is opaque, whitish, while it becomes horny, transparent and brown in alcohol. I cannot, 

 however, regard it as a gland. For first it has never any connection with the genital duct 

 (as may be seen in transverse sections) ; and secondly it does not e.xhibit the structure of a gland 

 in any way, but is t]uite homogeneous, without showing cells or nuclei, and diffusedly absorbing 

 colouring matter. Perhaps it is a secretion of some gland which, however, is not yet known itself. 



The penis, when invaginated, is club-shaped, and curved dorsall)' at its distal end. It 

 opens at the base of the right lateral lobe of the foot, as may be seen in transverse sections. 



A most curious fact in HalopsycJie is that this animal is ovoviviparous. This peculiarity 

 has been discovered already by Macdonald ') who found larvae in an advanced stage of 

 development. Nearly all the specimens of the Siboga enclosed larval stages in the connective 

 tissue beneath the skin. As the youngest stages were especially well represented, their study 

 is of the greatest importance. But I have thought it better to delay a full description of them, 

 as I intend to combine this study with other embryological researches on the Gymnoscjmata 

 at the Naples Station. 



Although I took great care, I have not been able to recognize with certainty the 

 heart or the kidney. Not one specimen possessed an organ which could answer to a circulatory 

 or excretory apparatus. This fact is the more to be regretted, as neither Souleyet nor Pelseneer 

 have been more fortunate. Souleyet mentions a sac (the heart?) at the base of the so-called 

 "gills" (the buccal appendages), and Pelseneer notes some "very delicate organs" at the 

 right-side of the body. 



I have found the central nervous system and the nerves issuing from it quite the same, 

 as Pelseneer described it. The visceral mass consists of three ganglia, while the pleural and 

 cerebral ganglia are fused together. There is only one nerve to the nuchal tentacle. The 

 cerebro-buccal connectives are remarkable for their shortness. 



1) Op. s. c, p. 246, pL XV, fig. 4, I, 9. 



2) Chall. Rep., LXVI, p. 53. 



3) On the anatomy of Euvybia gaudichaudi, Transact. Linn. See. Lond., vol. .\XII, p. 246, pi. .XLIII, tig. g. Some specimens 

 of the Challenger, which I examined in the British Museum, were also provided with young larvae, a peculiarity which escaped the 

 notice of Pelseneer. 



