520 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The histological characters of the central nervous system have been 

 specially investigated ; it contains ganglionic cells and fibrillar substance, 

 and a highly differentiated connective tissue. All the ganglionic cells 

 are unipolar and devoid of membrane, and lie in sheaths of connective 

 tissue. They are (1) cells with poorly developed body, darkly coloured, 

 highly refractive nuclei, small and irregular in form ; or (2) small, 

 elongated, club-shaped cells, with oval nuclei and one or more nucleoli ; 

 or (3) they are large, lightly coloured, flask-shaped, with large round 

 nucleus and one nucleolus; or (4) they are colossal cells, which quickly 

 take up colouring matters, and have a round nucleus with a projecting, 

 large nucleolus. 



The connective tissue is of two types ; one is like the neurilemma, 

 while the other consists of fibres which are given off from numerous, 

 dendritically-branched processes of membraneless cells ; they surround 

 in large numbers the ganglionic cells, and may be easily recognized by 

 their large oval nucleus and their peripheral zone of granules. 



Helminthological Notes.* — Dr. von Linstow has another of his 

 papers on new and imperfectly known worms. He has made an ex- 

 amination of the internal structure of Pseudalius minor, taken from 

 various organs in the common Porpoise. PJiysaloptera prsepuiialis sp. n. 

 was found in Brazil in Felis catus ; it is chiefly remarkable for, the 

 preeputium-like duplication of the skin at the caudal end of the body in 

 both sexes, Tr. campanula sp. n. is from the domestic cat of Brazil ; it 

 is possible that this is the same as the form which Diesing named 

 Tr. felis, but did not describe. 



Echinorliyncus Dipsadis sp. n. was found represented by flfteen 

 examples in the enteric wall of a large Dipsas Blaudingi from the 

 Cameroons, where it lived in its larval condition ; encapsuled Ecliino- 

 rhyncus-lavYse have been found in a number of snakes ; their adult forms 

 are probably to be sougiit for in birds of prey. 



Cercaria terricola sp. n. was found in the liver of Helix ? vermiculata 

 from Algiers, and C terrestris sp. n. from the same organ in H. lens from 

 Oreece. The author concludes with some remarks on the anatomy of 

 Bothriocephalus rugosus ; this species may be as much as 380 mm. long. 

 The muscles of the parenchyma are well developed, but those of the 

 subcuticular layer are very feeble. Of the former the longitudinal 

 muscles are the best developed. The nervous system consists of two 

 ganglia connected by a strong transverse commissure, and of two strong 

 longitudinal nerves invested in a sheath. Outside the nerve-trunks there 

 a,re ten vascular trucks, which are 0'016 mm. broad. On the whole, this 

 species of Bothriocephalus is very diflerent from B. laius, and recalls 

 rather the Tsenise of Birds. 



Herr G. Brandos f gives an account of a very small Distomum 

 (D. clavifonne sp. n.) which he found in large numbers in the rectum of 

 Tringa alpina. Its body is divided into a longer flat anterior portion 

 and a shorter spherical hinder part ; the latter contains the generative 

 apparatus. Another new species was fuund in the small intestine of the 

 frog; it is 2*5 mm. long, and it is to be called D. turgidum. The author 

 concludes with some notes on D. heieroporum from Vespertilio pipistrellus, 

 which seems to have been somewhat misunderstood by Van Beneden. 



* Arch. f. Naturgesch., liv. (1S89) pp. 235-46 (1 pi.), 

 t T. c, pp. 247-51 (1 pi.). 



