98 THE AMERICAN MONTHLY [May 
a Spurs none; foot ending in a disc-like sucker, 
with 10 posterior papille ; body with lateral 
skin-folds. In moss clauda. Q., 1893, 150 
Only Ome: BPeCies whiskies iis Nee) the eae el es kee clavus 
19. ASPLANCHNA. I., 120. Sup. 12. 
a Female with 4 humps; eye single. ooo Ebbesbornii 
a Female with 3humps; eye single oo. 2 eee amphora. Sup 
a Female with no humps; eye single, (b) 
a Female with no humps; eyes 3, (c) 
b’ “Male withonttt Wumips ee ee Brightwellii 
b Male with 4 humps; female like Brightwellii_......... Sieboldii. Sup 
b Male with 2 humps; female like Brightwellii.....intermedia. Sup 
c Head truncate; 1 cervical eye, 2 smaller, sub- 
marginal; ovary a transverse ribbon... .... triophthalma,. Sup 
c Head convex or conical; eyes in a nearly straight row ; 
Ovary FOUN a ee ee, Cae iii! ele eee priodonta 
20. Saccutus. I., 124. Sup. 16. (Ascomorpha, Perty.) 
a No longitudinal ridges; head conical, yellow, 
with triangular, dorsal, basal process............ ..Germanicus. Sup 
a No longitudinal ridges ; sac-like; head conical, no process..viridis 
a No longitudinal ridges; head with long, dorsal, 
straight, antennal process.oji6 a orbicularis. * 
a Four ridges; head truncate, with lip-shaped, dorsal 
EOCESG a saltans, Sup 
a Two lateral, subdorsal grooves; head depressed; 
Fo, WE Es Rasa Dip aM TES DRAMA RRRIeTT Ror! ire ihe AO ney Ree Ae hyalinus. Sup 
21. SyNcH#TA. I., 125. Sup. 17. 
a Fresh-water, (b) 
a Marine, luminous; cylindric, conical behind... Baltica 
b Body a swollen cone, (c) 
b Body a slender cone; heaé truncate, auricles in its plane. tremula 
b Body ovate or pyriform; head very large, auricles wide, 
rounded; foot none, toe 1, minute oblonga 
©: Atricles long,’ pointed, pendent is oe ee ae pectinata 
c Auricles long, pointed; foot long, rhomboid, toes 2_longipes. Sup 
c Auricles large. rounded; foot long, slender o.oo... stylata. + 
22. POLYARTHRA. IL,, 3. 
a Spines 12, narrow...... ...... platyptera 
a Spines 12, broad, leaf-like oi eee iaveciiolece. Q., 1896, 267 
a Spines absent... .. i aptera. Q., 1893, 281 
* Kellicott. Trans. Am. Micros. Soc., 1897, 46. 
Jennings. Bul. Mich. Fish Com., 1894, 10. 
