ZOOLOGY AND BOTANY, iriCROSCOPY, ETC. 589 



Five different modes of reproduction are known among the Syllidaa : — 

 (1) By direct reproduction, as in a number of forms. (2) By alternate 

 generation and fission, and then by budding from a single stolon, as in 

 Syllis hcanata, S. Krohiii, and others ; the stolones of the different genera 

 always differ from the stock, and they differ also among themselves in 

 the forms of their heads, of which there are four distinct types, that of 

 SijUis arnica, that of ChsetosyUis, of Tetraglene, and of loida. (3) There 

 may be reproduction by successive alternating generations, at first by fission 

 with a single stolon, then by budding with a single stolon, and lastly by 

 budding with several stolons in a chain, all the chains having for males the 

 forms of Poli/boslrichus, and for females that of Sacconereis ; here we find 

 Autolytus, Myrianida, Vircliowia (?), and Frocerastea ('?). Viviparous repro- 

 duction has been proved in two cases ouly, in S. vivipara and S. incisa. 

 (5) Reproduction by lateral gemmation occurs in Syllis ramosa, where the 

 stolones have the form of Tetraglene. There are as yet a number as to the 

 mode of whose reproduction we are still ignorant. The descriptions of the 

 species commence with that of Syllis hamata, under which must be included 

 the varieties regarded by Czerniavsky as specifically distinct. S. variegata, 

 S. prolifera are followed by S. alternosetosa sp. n. which is extremely 

 common ; its head is provided with four small eyes without a crystalline 

 lens, the setee are of various kinds, and remarkable for their complete 

 alternation. S. sestlieiica is also a new species characterized by the form 

 of its setaa. Under S. gracilis Czerniavsky has distinguished four species, 

 which must be united. Pionosyllis is accepted with the emendations of 

 Langerhans. P. longocirrata sp. n. is distinguished by having the dorsal 

 cirri of the anterior segments excessively long ; transparent organs termi- 

 nating in a cfecum surround the proboscis ; the author is unable to ascribe 

 any function to these long tubes, of which there are ten. P. lamelligera 

 sp. n. is in some respects intermediate between Pionosyllis and Eusyllis, 

 having, like E. lamelligera, the first ventral cirrus lamelliform and two 

 glandular tubes attached to the sides of the proboscis. Syllides longocirrata 

 is redescribed. Eusyllis is regarded as the bond of union between Pionosyllis 

 and Odontosyllis, and nearer the former ; the five species found at Dinard — 

 E. lamelligera, E. monilicornis, E. hlomstrandi, and E. intermedia sp. n. — are 

 all fragile and phosphorescent. Four species of Odontosyllis, of which O. 

 ■polyodonta sp. n. has a very large number of small teeth, are mentioned. 

 The possession of a large conical tooth must be added to the definition of 

 the genus Trypanosyllis, which is represented at Dinard by two species. 

 Pterosyllis spectahilis is carefully described ; this species often has its body 

 and long dorsal cirri covered with Trichodina Auerbachii, and a curious 

 marine infusorian which was described but not named by Claparede ; it 

 may be called Ophryodendron annulatorum. Eurysyllis paradoxa in its various 

 stages is described. 



Gruhea clavata, G. pusilla, Sphserosyllis hystrix, and S. erinaceus are 

 described. With regard to Langerhans's supposition that PsedopJiylax 

 exhibits alternations of generation. Baron de Saint-Joseph expresses the 

 opinion that the German naturalist based his view on animals which had lost 

 their proboscis and proventriculus. Seven phases of P. claviger are 

 described. 



The genus Autolytus must include Procereea and Stephanosyllis ; the 

 author gives an emended definition. A. paradoxus sp. u. is distinguished 

 by having, from the third segment, the dorsal cirri alternately short and 

 long. A. loiigiferiens sp. n. has an exceptionally long proboscis which is 

 terminated by a crown of ten large obtuse teeth, separated from one another 

 by three small pointed teeth. A. ornatus, A. pictus, and A. macroph- 



