1889.] Einbryology. 923 
the finer branches of the glosso-pharyngeal, accessory, and hypoglossal 
nerves. Neither paper is capable of abstract, while the adoption of 
the Wilderian adjectives and adverbs renders them somewhat pedantic 
and obscure. 
Dr. Frederick Tuckerman has recently published several articles 
upon the taste organs of mammals. In the Anatomischer Anzieger 
occur descriptions of these organs in Putorius vison, (Vol. III., p. 941), 
Arctomys monax, (Vol. IV., p. 334), Perameles nasuta, (Vol. IV., p. 
441)- In the latter he finds lateral taste areas overlooked by Poulton. 
In the American Journal of Science for October, 1889, he describes 
the organs in the common hare. In the Journal of AnatoMy occur 
accounts of the taste organs in Vulpes vulgaris (Vol. III., p. 201). 
Leboucq {Anat. Anz., IV.) finds that on the digits of the fins of 
foetal Sirenia and Cetacea there are evident traces of claw-forming 
epithelium. On the dorsal surface of each digit there is an insinking 
of the epidermis like that which precedes the formation of nails and 
claws in other mammalia, but no claw is formed by it. 
ExMBRYOLOGY. 
The Development of Micrometrus aggregatus, one of the 
Viviparous Surf-perches.— At a recent meeting of the San Diego 
(Cal.) Medical Society, Dr. C. H. Eigenmann presented the results of 
his further studies upon the earlv viviparous development of the very 
minute ova of Micrometrus aggregatus. The differences in the modes 
of segmentation were pointed out, and a comparison of the embryonic 
membranes of the different major types of amniotic vertel)rates was 
made. The effect of the loss of a large food-yolk, as illustrated upon 
comparing the tgo^ of a mammal and a bird, was shown to resemble a 
similar loss of food-yolk in the eggs of Micrometrus as compared with 
other large-yolked oviparous fish eggs. [The eggs of Microtnetrus 
<^ggregatus are the smallest fish ova yet described, measuring only a 
little over i-i4oth of an inch, or less than those of most mammalia, 
thus showing the profound influence of viviparity in causing a diminu- 
The following are Dr. Eigenmann's most recent observations:— 
The average pelagic fish egg has a diameter of about i mm. ; only 
