522 SUMMARY OF CURRENT RESEARCHES RELATING TO 



open by a small cleft outwards. Secondary are given off from tlie primary 

 trunks, and all the trunks form anastomoses with one another. 



The brain has the form of a kidney-shaped group of ganglionic cells 

 which lies just above the mouth ; four ocelli may be noticed in it ; a 

 second group of cells lying just behind the mouth may be called the 

 oesophageal ganglion. Four to six nerves are given off anteriorly from 

 the brain ; four nerves run along the ventral surface of the body ; these 

 nerves are easily recognized in stained transverse sections of the body ; 

 a third pair of nerves, which are much thinner, are placed on the dorsal 

 surface. In the middle of the brain lie four ocelli ; each of these con- 

 sists of a spherical lens surrounded by a layer of pigment ; on the free 

 side of each is a small highly refractive spherule which, possibly, acts 

 like the condenser of a Microscope. These ocelli are remarkable for 

 lying not in the cuticle, but in the centre of the brain, so that they are 

 covered externally by a layer • 14 mm. thick. It seems clear, therefore, 

 that they cannot have the function of recognizing images, but can only 

 be able to distinguish light from darkness, as is the case with the eyes 

 of various Vertebrates which are covered by the skin. 



The body-parenchyma, which stains feebly, is not cellular in structure, 

 but consists of a fine fibrous ground-substance, in which are rounded or 

 angular nuclei, 0*02 mm. in size. There is one ovary, and a pair of 

 testicles ; the seminal vesicle has very strong walls ; the cirrus is large 

 and spindle-shaped, and lies to the left of, and just beneath the mouth. 

 The ovary is rounded, and is placed just in front of the testes ; super- 

 ficially the two organs are very much alike. The vitellaria are very 

 widely distributed in the body, and lie in a dorsal and a ventral plane ; 

 the ootyp is spindle-shaped, and in it there is always found only one 

 egg. The shell-gland is of great extent, and consists of a large number 

 of pyrifurm glands with long efferent ducts. The ova are rhomboidal, 

 irregular, or triangular in form ; at the hinder end there is a filamentar 

 appendage of varying length. There is no canal of Laurer ; a com- 

 parison of various forms shows that by this term, organs of various 

 functions are spoken of. Like the two other species of Phylline, the 

 development of P. Hendorfii is unknown ; it is doubtless monogenetic, 

 and its embryos swim about in water by the aid of an investment of cilia. 



The author points out the differences between the three species, and 

 concludes with enumerating the generic characters of Phylline. 



Nervous System of Amphiptyches.*— Dr. F. S. Monticelli has, in the 

 course of his researches on AmiiJiiptyches, elucidated the nature of the 

 nervous system, which has hitherto been known only through a brief 

 notice by Wagoner. It consists essentially of two lateral ganglionic 

 swellings, situated in the antei'ior portion of the body, and united by a 

 transverse commissure. Four nerves, two anterior and two posterior, 

 rise from the two ganglionic swellings. The whole system, of which the 

 details are described, lies rather towards the ventral surface. Morpho- 

 logically the system agrees with the general cestode type, and closely 

 resembles that of the simpler Cestodes, especially that described by 

 Lang in AmjpJdlina foUacea Wagen. 



Cercaria setifera.t — Dr. F. S. Monticelli has a preliminary notice 

 on a Cercaria with a long tail and lateral bristles, which occurs in the 



* Zool. Anzeig., xii. (1889) pp. 142-4. 



t Bol. Soc. Nat. Napoli, ii. (1888) pp. 193-9. 



