178 AETHUE E. SHIPLEY. 



from the scanty material at our disposal, with reference to the 

 geographical distribution of this Gephyrean. Nevertheless, so 

 little has been done with regard to the distribution of the 

 lower marine invertebrates, that it seemed to me to be worth 

 while to put together what is known about the occurrence in 

 space of the genus I have been lately working at. The most 

 striking deductions from the facts before us are — (i) the import- 

 ance of the Malay Archipelago as the headquarters of the 

 genus, but this is possibly more apparent than real; (ii) the 

 restriction, with few exceptions, of the genus to tropical seas ; 

 and (iii) their preference for shallow waters. The last two 

 generalisations are obviously connected with the fact that the 

 animals only flourish in comparatively warm water. 



In conclusion, attention may be drawn to the association of 

 these animals with coral islands. This may be accidental, and 

 due to conditions of temperature only ; but, on the other hand, 

 several species make their homes in tubular holes burrowed 

 out in the soft coral rock. 



The Moephological Laboratoey ; 

 Cambeidgb, July, 1890. 



