226 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the perforations are usually central, but not always. The histological 

 features are described, and the "various opinions on the subject are noted. 

 The author regards the anomaly as primarily an integumentary 

 variation, — "an irregular, abnormal development of the cuticle of some 

 of the rings, resulting in a kind of pathological condition, completed 

 by an external digestive action." 



Intermediate Host of Taenia cucumerina.* — Professor B. Grassi 

 communicates a preliminary note in regard to the intermediate host of 

 Tsenia cucumerina. This is usually supposed to be the louse Trichodectes 

 latus, as has indeed been demonstrated, but Grassi was led to doubt this 

 on account of the rarity of the " louse " compared with the abundance 

 of the tapeworm. His experiments inclined him in fact to suppose that 

 the development might be direct as in T. murina. Now, however, he 

 has been led to regard it as more probable that the ordinary intermediate 

 host is no other than the flea (Pulex serraticeps). 



Structure of Bipalium.f — Dr. J. C C. Loman has a memoir on the 

 genus Bipalium, twenty-one species of which have already been more or 

 less completely described. Kuhl and v. Hasselt examined forms which 

 are now to be called B. vittatum and B. marginatum, and the author 

 describes as new B. moseleyi from Borneo, B. sumatrense from Sumatra, 

 and B. javanum from Java. 



In dealing with the integument the author raises objections to 

 Moseley's explanation of the disappearance of cilia in certain parts being 

 due to the expulsion of large numbers of i-od-like bodies, and contends 

 that these are tegumentary cells which are not ciliated ; in fact he declares 

 that the cilia of the surface are confined to what he calls the ambulacral 

 bands. The rod-cells are regarded as mesenchymatous structures which 

 wander through the surrounding connective tissue, while their contents 

 become converted into filamentar rods. Mucous glands are especially 

 numerous, and are found over the whole body ; their efferent ducts do 

 not appear to have special walls, and the granulated mucous filament is 

 found lying in simple lacunsB of the connective tissue. 



The number of layers in the dermomuscular tube appears to vary 

 somewhat in Planarians ; in Bipalium dorsovcntral and transverse 

 fibres are present in addition to oblique (with a few circular), external 

 and internal longitudinal fibres. There is really a kind of muscular 

 foot such as is not known even in other Land Planarians. The majority 

 of the muscles are homogeneous, and do not even exhibit a differentiation 

 into cortex and medulla. B. javanum is strongly pigmented, and the 

 colour is due to small black granules which are collected in the connective 

 tissue cells and their fine processes ; the pigment is not confined to the 

 surface of the body, whereas it is in B. sumatrense very rare in any other 

 than the superficial parts. 



The investigation of the nervous system is a matter of some difficulty, 

 as the cells and fibres are not easy to distinguish from the larger 

 mesenchym cells, but the nuclei of the connective tissue are always 

 smaller than those of the ganglion cells, and are always much more 

 intensely coloured by hsematoxylin and borax-carmine. Professor Mose- 

 ley's account of the histology of the eyes is stated to be correct. The 



* Bull. Soc. Entom. Ital., xx. (18SS) pp. 66. 



t Bijdragen tot de Dierkimdc, xiv. (1887) pp. 63-88 (2 pis.). 



