lO RESEARCHES IN HKLMINTHOLOGY AND PARASITOLOGY. 



applied to two semi-transparent lines passing along each side of the 

 ventral surface, and a third along the middle of the dorsal surface, 

 the three freely communicating with each other by transverse lines 

 and numerous smaller branches, the whole forming an extensive 

 reticulation upon the surface of the body. At the anterior part of 

 each ventral line I distinctly observ^ed a dilatation to exist. 



Gcjierative apparatus. — As in all Planariae, the animal is androgy- 

 nous. The penis is a bulbiform organ placed between the oral and 

 generative orifice, with its point directed toward the latter. The 

 point is straight, or contorted ; the bulbous portion is also change- 

 able, sometimes elongated, at others flattened or increased in breadth 

 at the expen.se of the length. The bulb shows through the thin 

 integument, and without close examination may be taken for a third 

 orifice. The penis is perforate, and has a dilated cavity within the 

 bulb. Immediately above the penis I indistinctly observed a some- 

 what lobated organ, which appeared to join the penis at its base by a 

 narrow portion. This is probabl> the testicle, for it was the only thing 

 I could discover in connection with the genitalia to correspond to it. 



In tw^o individuals only could I see part of the female organs. 

 This consisted in two sigmoid tubes or oviducts, which could be 

 traced from the generative orifice a short distance forward, one on 

 each side of the penis. 



I could detect no traces of a nervous system. 



The eyes, so called, have been previous!}- described. It is still a 

 question with many, whether these, as well as the corresponding 

 deep black points existing in very many of the lower animals of the 

 invertebrate .series, sub.serve the purpose of eyes ; and some anato- 

 mists have even gone so far as to deny the sen.se of sight to the 

 comparatively perfect eye of many gasteropodous mollusca. The 

 experiments which are made to test the existence of this sense in 

 the.se organs for the most part are exceedingly fallacious, generally 

 being performed by concentrating the light upon them through a 

 lens. Insects, and even serpents and frogs, I find will frequently 

 bear the impression of a sudden glare of light produced in this way 

 without any inconvenience, at other times they will seek to avoid it, 

 but I/clix albolabris will occasionalh' retract its tentacle when so dis- 

 turbed, and Phagocata will frequently raise its interior extremity and 

 move from the too great light. From their position, which is always 

 such as to be well exposed to the influence of the light, from their 

 structure, imperfect as it is in many cases, and their connection with 

 the nervous system when this exists, I am led to conclude that in 

 all ca.ses they are organs of vision. 



