﻿The Symjwfhi. 



131 



plenty more in those other details of the organism which cannot 

 well be studied without dissection and microscopic examination. 

 The mandibles may have the trunk pointed at the base or very 

 blunt, the molar stout or slender, spines of the spine-row numerous 

 or very few ; the palp of the first maxillae may end in two filaments 

 or only one, or the palp may be missing altogether ; important 

 variations in the terminal joints of the first maxillipeds are indeed 

 more or less easily discernible, but this is not the case with the 

 branchial apparatus which is out of view in complete specimens, but 

 which has important differences to offer in the number and disposi- 

 tion of the branchial leaflets. Even the comparative uniformity of 

 the intestine cannot be depended on, since Cyclaspoides mrsi, 

 Bonnier, and Platycuma holti, Caiman (Fisheries, Ireland, 1904, I. 

 [1905], p. 30, pi. 3, figs. 39-56), agree with many of the Cladocera 

 in having a coiled instead of a straight ahmentary canal. 



It is reasonable to suppose that the Malacostracan type of body 

 was gradually produced in far-distant ages, but the pattern is now 

 so wonderfully persistent and traceable under all sorts of disguises, 

 that missing parts are almost certainly due to losses, not to inherit- 

 ance of ancestral defect. Hence, as above suggested, we may be 

 allowed to assume that the organism with the largest number of 

 distinct parts comes nearest to the original pattern. On this 

 principle the family Vaunthompsoniidge will stand first, having in 

 the male five pairs of pleopods together with exopods on the first 

 four pairs of perajopods, and in the female exopods on the first three 

 of those pairs. The Sympodommatidse agree as to pleopods, but 

 have exopods only on the first three pairs of peragopods in the male 

 as well as in the female. The Bodotriidas with the same number of 

 pleopods have well-developed exopods only on the first perseopods in 

 each sex. The only other family with five pairs of pleopods is the 

 Ceratocumatidse, which might claim precedence over the famihes 

 already named in respect of its distinct telson, which they are with- 

 out, but it is inferior to the Vaunthompsoniidye by having exopods 

 in the male on the first two only instead of the first four pairs of 

 perEeopods, and in its only known species it has lost the fifth 

 perseopods altogether. 



The present essay proposes the adoption of fourteen new species, 

 nine new genera, and a new name for a genus already known, but 

 a more im.portant innovation affects the framework of the group at 

 large. In view of a forthcoming monograph, which avowedly aims, 

 not at introducing novelties, but simply at recording the actual state 

 of science, it has seemed desirable here to name a great number of 



