April, 1908. Lakes Amatitlan axd Atitlax — Meek. 201 



Length in moderately extended resting condition 25-30 mm., 

 maximum width at posterior end of clitellum 3 mm., greatest 

 depth nearly 2 mm. 



Egg-cases very flat, thin, yellowish, chitinoid capsules, ellip- 

 tical, not produced at the ends, and with slightly developed thin 

 margins; 3-4 . 5 mm. long and 2-3 mm. wide. They are attached 

 by one face to the under-side of stones, sticks, etc., and each con- 

 tains several eggs or young immersed in albumen. 



In the digestive tracts were found the remains of small insect 

 larvae, oligochaete annelids, and other leeches, including their 

 own species. 



Very abundant under rocks about the shores of Lake Amatit- 

 lan, Guatemala, associated with Glossiphonia lineata (Verrill) 

 Moore. I have also received specimens from other parts of Cen- 

 tral America, Mexico, and the mountains of southern California. 



A small, slender leech, seldom exceeding 30 mm. in length, 

 pale ashy below and of a yellowish olive or dull green color above, 

 marked by two or four dusky longitudinal stripes, which may be 

 diffuse and coalesced. On the head are three pairs of eyes, the first 

 and largest on the upper lip, the other close together at the sides of 

 the mouth. In addition to some features of the internal structure, 

 this species is distinguished from related leeches by having all of 

 the rings of the middle of the body of equal length and similar 

 structure, and three complete rings intervening between the male 

 and female external genital pores. 



It abounds about the shores of Lake Amatitlan, seeking con- 

 cealment by day beneath stones and similar objects in the shallow 

 waters, and at night becoming active in the pursuit of small 

 worms, insect larvae, and even the smaller members of its own 

 species, which constitute its chief food. Having no toothed jaws, 

 it is not an habitual blood-sucker, though it doubtless, like related 

 species, attacks abraded surfaces of higher animals when oppor- 

 tunity offers. 



Not confined to Lake Amatitlan. It has been found through 

 Central America, Mexico, and in the mountains of southern Cali- 

 fornia, inhabiting streams as well as lakes and ponds. The eggs 

 are deposited, several together, in a quantity of albuminous jelly, 

 in small, very flat, elliptical, somewhat horny capsules, provided 

 with a thin, often frilled border, and attached firmly to the under 

 side of stones. 



Type No. 2389 Collection Academy of Natural Sciences of 

 Philadelphia. 



