358 



ZOOLOGY. 



as to leave even its relationship a matter of discussion. G. O. Sars dis. 

 tinguishes it as a group (Telobrancliiata) of the Opisthobranohiates 

 co-ordmate with the Tectibranchiata and Xudibranchiata. H von 

 Ihering- differentiates it as a class of ^'Yermes— Phylum Amphineur-i " 

 the Chitons forming another class. E. Eay Lankester isolates it still 

 further, considering it as representing not only a class (Scolecomorpha) 

 but a primary group (Lipoglossa) of Mollusks having no affinity to the 

 Chitons. A new form of this group, exhibiting characters, too, deemed 

 wanting m the type, must be of unusual interest. Such is the species 

 made known as Proneomema muiterl* Like Neomenia, Proneomenia is 

 worm-like and subcylindrical, but unlike that form it is provided with a 

 distinct though small radula. Two specimens of the species were 

 dredged by Dr. Sluiter in the Bareut Sea. 



REGENERATION OF PARTS IN GASTROPODS. 



Long ago Spallanzari and afterwards Schaffer experimented upon the 

 regeneration of parts in snails, but this subject has since l>een much 

 neglected. Eeceutly Mr. Justus Carriere has reinvestigated the cpies- 

 tionf, and has found, like his predecessors, that the tentacles, with the 

 eyes and the labial processes in tlie gastropods, can be completelv 

 regenerated. On the other hand, when the pharynx or supra-oesopha- 

 geal ganglion is cut out death ensues. Mr. Carriere took all precau- 

 tions m his investigations, and all the conditions to insure accuracy 

 were fulhUed, that is, with respect to the health of the animal the 

 parts removed, &c., for a different result would ensue if the animal was 

 taken when its energy was concentrated in the formation of generative 

 products, and it was therefore found that a season of rest, as at the 

 beginning of summer, or the autumn season, was the most satisfactory 

 time. The individuals experimented upon represented common Euro- 

 pean species of Ildix. Those that gave the most satisfactory result 

 were^e^*^ nemoralis and R. hortensis; H. pomatia was more sensitive 

 and H. arhustarum and U.fruticum the least capable of reproduction of 

 parts. 



In the case of the eye it was ascertained that the method of reo-ener- 

 ation was analogous to that of the first formation of the organ Tliere 

 was an invagination of the epithelium, the formation of a closed vesicle, 

 and the primitive cylindrical cells became i)artly converted into corneal 

 (Jells, and partly into rods and cones. The time required for this re- 

 generation was fifty or sixty days. 



Experiments were also instituted with respect to the aquatic pulmon- 

 ates but the results were less satisfactory on account of their liability 

 to attack by fungus in the wounds. 



fc^Z ^"« ^^em Eismeer. Zool. An.ei.er, iii Jabrg., pp. r,89-590, 29 Nov., 1880. 



rlr. 7Ti V, f R<^Seneration bei den Land-Puhuonaten. Ta.jhlatt der 52 



» as. deutsch. 2\aturf., pp. 225, 22o. 1879. 



