HISTORICAL REVIEW. 15 



In 1SS2 Kowalcvsky and Clarion called in ciucstion the work of all pre- 

 ceding authors, claiming that they in every case had wrongly oriented the ani- 

 mals, that the anterior end is in reality posterior and I'icc versa. Tullberg's 

 lateral glands (portion of the coelomoducts) are accordingly the salivary glands, 

 the penis with its appendages is clearly the radula, the mouth cavity is the 

 rectum, the "egg bag" (pericardium) is the intestinal coecum above the pharynx, 

 the branchia are the buccal cirri and finally the protrusible pharynx is the com- 

 bined uterus and oviducts. 



This paper called forth an immediate rejoinder on the part of Hubrecht, 

 who reviewed the work of the authors in cjuestion, and showed that the orienta- 

 tion of the animals in question is correct, and that Kowalevsky and Marion have 

 created confusion worse confounded owing, for one reason at least, to the fact 

 that they had not seen the species under discussion. 



During the next four or five years Kowalevsky and Marion published, 

 either separately or conjointly, several papers preliminary to their chief work 

 wliich appeared in 1887. In this study the authors describe to a certain extent 

 the habits of five new species of these molluscs collected along the shores of 

 France, and accompany it with a very detailed description of the external 

 and internal anatomy. Some of these last named results are referred to else- 

 where in the jiresent pajier. 



In the meantime Selenka ('85) inil)lished an account of the gephyrean worms 

 collected by H. M. S. Challenger, and therein l)iiefly described Chaetoderma 

 tnililiirr from the Malay Archipelago, adding the remark that he was unable 

 to give any tlata that might settle its systematic position. 



In 1888 Hubrecht described a new genus of iSoIenogastres (Dondersia) 

 taken in the vicinity of Naples. It is a fairly close relative of Proneomenia and 

 Neomenia, and the anatomical characters are accordingly not strikingly differ- 

 ent from those presented in the paper on P. sluiteri. 



In this same year Hansen ('88) made a stud}' of several species of Soleno- 

 gastres long before described by Koren and Daniellssen ('77). His researches 

 chiefly concern Neomenia cariiiata, which is shown more conclusively than be- 

 fore to be similar to P. sluiteri. Chaetoderma nitidulum was found to pass the 

 sex prnducts iiilci the jieiMcardium from whence they pass through ducts into 

 the anal cavity (Hubrecht) or branchial cavity (Hansen). 



Pruvot ('90) denied the existence of a heart, or pericardimn or dorsal aorta 

 in the Solenogastres. The blood moves in lacunae of which a large one passes 

 dorsally along the mid line propelled by contractions of the body. The paired 



