ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 175 



towards the centre, until soon little is left save the disc. The ease and 

 swiftness with which the autotomy takes place is very remarkable. Other 

 more or less familiar cases described by the author are the throwing-off 

 of the marginal tentacles by species of Lima, of papillae by Eolids, and 

 by Tethys leporina, of the arms by Octopus dcfilippii, and the limbs by 

 various Crustacea. The paper is entirely descriptive, no suggestions as 

 to the use of the habit being made in any case. 



Additions to British Fauna.* — Andrew Scott gives a list of new 

 records, including many fish-parasites from Liverpool Bay. Some of 

 the forms mentioned have not hitherto been described in the British 

 area. In the brain of a specimen of Lophius piscatorius cysts of the 

 Protozoon Glugea lopliii were found, a form previously known only from 

 the Mediterranean. Among the parasitic Copepoda, a new species of 

 Galigus (G. brevicaudatus) occurred, while C. brevipedes Basset Smith 

 was found in abundance, and owing to the structure of the fourth pair 

 of legs, is referred by the author to a new genus, Pseudocaligus. 



Homologies of Coelom.f — Joh. Thiele gives a summary of the views 

 on this question which he intends to put forward in a forthcoming work 

 on the phylogeny of the Mollusca. The Mollusca in the general case 

 possess only a ha3mocoele ; a secondary body-cavity is not a universal 

 characteristic of them or of their ancestors, but in certain isolated cases 

 the primitive ducts of the gonads have become greatly enlarged, and so 

 produced cavities which resemble a secondary body-cavity. Such are 

 the right nephridia of Fissurellidaa and the pericardium of Cephalopoda. 

 The author believes that the designation ccelom should be avoided in 

 both these cases, but if it is used then, as both cavities are excretory, the 

 term nephroccele must be employed. Quite different from these cavities 

 is the body-cavity of Annelids, which the author regards as having arisen 

 as a lymph-space by the absorption of parenchyma, and therefore as 

 comparable to, though separate from the htemoccele, with which however 

 it may become secondarily united. This Annelid body-cavity may be- 

 come secondarily connected with the sexual organs, a process in regard 

 to which the following series of stages exists : — In Neomenia there is a 

 regular series of segmentally arranged gonads connected with a longi- 

 tudinal duct which opens to the exterior at the posterior end of the 

 body. In the Gordiidae the gonads have the same relations, but the 

 longitudinal duct is not able to carry the whole of the generative pro- 

 ducts, which burst through its thin wall and enter the body-cavity. In 

 Polygordius there is no longitudinal duct, and the generative products 

 fall directly into the body-cavity, whence, finding no exit, they burst 

 through the body-wall. In certain Polycluetes the primitively excretory 

 segmental organs become enlarged and take on the function of genital 

 ducts. Finally, in the higher Annelids, the gonads become limited to 

 the anterior region of the body-cavity, and from part of the body-cavity 

 there arise special genital ducts not homologous with the excretory seg- 

 mental organs. In consequence the author holds that the gonoccele 

 theory is not true for the Annelids, for in them the cavities of. the 

 gonads and their ducts have degenerated, and there is no homologue of 



* Proc. and Trans. Liverpool Biological Soc, xv. (1901) pp. 342-53 (3 pis.), 

 t Zool. Anzeig., xxv. (1902) pp. 82-4. 



