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Page 109. Add the following genus and species: 



Gen. Scottomyzon, Giesbrecht, 1897. 



Generic Characters. Body short and stout, with the anterior division 

 very sharply marked off from the posterior and greatly dilated, especially in 

 female. Rostral prominence obtuse, incurved. Tail very small and consisting 

 in female of only 3, in male of 4 segments; genital segment in both sexes 

 greatly tumefied. Caudal rami short, with the usual number of setae. An- 

 terior antennas not much produced, but, as in most other Ascomyzontidae, 

 divided into numerous short articulations; those in male distinctly hinged near 

 the end, but without any supplementary aestethasks. Posterior antennae with 

 the appendicular (outer) ramus more fully developed than in the other Asco- 

 myzontidae. Siphonal tube quite short, with large opening. Mandibles with 

 the masticatory part not much produced, palp small, unisetose. Maxillae with 

 both lobes well developed and nearly equalsized. Anterior maxillipeds much 

 more strongly built than the posterior. Natatory legs with the rami compara- 

 tively slender, terminal joint of the outer one with only 2 spines outside. 

 Last pair of legs small, biarticulate. 



Remarks. This genus was established by Giesbrecht to include a 

 species first described by T. Scott and referred by him to the genus Derma- 

 tomyzon of Glaus. It is chiefly characterised by the short and stout form of 

 the body, the unusual size of the outer ramus of the posterior antennae and 

 the very strong development of the anterior maxillipeds; finally by the peculiar 

 structure of the siphonal tube. Only a single species is as yet known. 



Scottomyzon gibberum (Scott). 



(PI. CXVI). 



Dermatomyzon gibberum, Scott. On some new and rare Crustacea from Scotland. Ann. Mag. 

 Nat. Hist. Ser. 6, Vol. XIII, p. 144, PI. IX, figs. 1014. 



Specific Characters. Female. Form of body very short and compact, 

 more so than in any of the other known Ascomyzontidae. Anterior division 

 of somewhat varying shape according to age, being in young specimens sub- 

 clavate or pear-shaped, in fully adult specimens nearly circular in outline, with 

 the greatest width about equal to the length. Cephalic segment exceedingly 

 large, with the lateral edges quite evenly arcuate throughout. The succeeding 

 segments rapidly diminishing in size, and having the epimeral plates rounded 

 off. Tail very short, being scarcely Vo as long as the anterior division ; genital 



