1891.] Zoology. 667 
tology is described, but is not easy to understand without figures, His 
conclusions are that the lack of homology between the brain of Limu- 
lus and Arachnids, the shape and grouping of the appendages, the 
absence of urinary tubes, of trachez, the presence of branchiz, forbid 
the association of Limulus and its fossil allies with the Arachnids, 
although they may have had a common origin. 
The Vertebrate Ear.—Dr. Howard Ayers, from a study of 
mammalian and sauropsidan ears, concludes™ concludes that the so- 
called membrana tectoria of the mammalian cochlea is not a mem- 
brane which acts as a damper on the organ of Corti. He rather 
regards it as an artifact produced from the very long sense hairs of the 
cells of the cortian organ. The membrana basilaris further is not a 
vibrating membrane. ‘‘ The physiological unit of the cochlea is a 
sensory hair-bearing epithelial cell; the anatomical unit of the 
cochlea is a group of hair-bearing and supporting cells,—7. e., a sense 
organ comparable in a word to an ampullar sense-organ."’ Full details 
are promised immediately. 
Segmentation of the Vertebrate Head.—B. H. Waters 
thinks !3 that the neuromeres of Beranek and others may be traced 
into the mid- and fore-brains of Amblystoma and the cod, and he 
would recognize three neuromeres in the fore-, two in the mid-, and 
six or five in the hindbrain. The optic nerve is given a segmental value. 
Description of a New Species of Catostomus (C. rex) 
from Oregon.—One specimen, thirty-two inches long, from Lost 
River, Tule Lake, Oregon, was added last year to the collection of the 
California Academy of Sciences. The characters are as follows: 
D. II., 1114; A. II., 6%. Scales, 13-80-8 ; about 35 before the dor- 
sal. Head, 4; depth, 4. Eye, 8 in head, placed but little posterior 
to the middle, the snout about 21% in head. Head broad, flattish, the 
cheeks sunken and very long. Mouth small, lower jaw strong, the 
maxillary spine forming a hump on the snout. Papillz small, appar- 
antly but two rows on upper lip. Scales peculiar, the basal portions 
covered with skin. Ventrals rounded, placed below anterior half of 
dorsal, not reaching halfway to vent. Dorsal as high as long, angu- 
lar, the last rays but little shorter than the anterior, inserted midway 
between tip of snout and base of middle caudal rays. Pectorals reach- 
ing halfway to ventrals. Caudal peduncle subterete, long. Anal just 
reaching to caudal. Lateral line interrupted posteriorly. Pharyngeals 
12 Anatom. Anzeiger, VI., p. 219, 1891. 
13 Zool. Anz., XIV., 141, 1891. 
