GAKMAN: THE ClilMAEllOIDS. 263 



have two pairs of teeth above and one pair below, like recent members of the 

 group, but the dorsal spine is absent, the body is depressed, and the frontal 

 tenaculum of the male is t-longate st\liforni, much as the proboscis itself; and 

 the Myriacanthidae have the dorsal spine, have dermal plates on the head, 

 and have two pairs of teeth above and one pair an 1 a single symphyseal tooth 

 below. 



A number of features are possessed in conuuou by the living forms, features 

 by which they are closely linked together and by which they arc readily dis- 

 tinguished from their nearest allies of the Plagiostomia. The form of body or 

 the general shape, the mandibular susjiensorium, the teeth, the lateral system, 

 the lack of shagreen, the erectile first dorsal, the frontal tenaculum, and the 

 ventral tenacula of the males, the wide separation of hemispheres and optic 

 lobes of the brain, the articulation of rostral cartilages; these go to distin- 

 guish the Chismopnea from the Plagiostomia. For family characters depend- 

 ence is placed on the differences in regard to the proboscis, on differences iu 

 the structure of the notochord, on differences in the claspcrs, and on differ- 

 ences in the brain and in the lateial line. The generic and the specific sepa- 

 rations are made by differences in the details of tritoral development, by the 

 slighter variations in forms of rostra, or in the structure of claspers, by minor 

 differences in the distribution of the lateral line, in the lengths and shapes of 

 the fins, in colors, etc. 



The partial descriptions given below are introduced not as redescriptions 

 but as additions to knowledge of several species, rare or not easily secured, to 

 which references have been made in this paper. The lists of genera and 

 species recognized herein are given under the classification. 



Harriotta raleighana. 



Plate 3, Figs. 3-5; Plate 4, Fig. 1; Plate 5, F;ss. 3-9. 



Hamolta raleighana Goode and Bean, 1894, Proc. U. S. Mus., xvii. 472, Plate XIX. 



Figs. 1-4. 



The authorities of the United States National Museum have kindly permitted 

 examination of some of the types from which this genus and species were origi- 

 nally descrilied. In consequence it is possible to add some items to the data 

 already published. Xecessarily they are limited to external features, as the 

 specimens could not be dissected. 



Specimen 35631, from the Xorth Atlantic (Lat. 39° 12' N.; Lon. 72° 3' 

 30" W.), at a depth of seven hundred and seven fathoms, is the original of 

 Figs. 1 and 2 on Plate XIX. of Vol. xvii. of the Proceedings of the Xational 

 Museum, 1894, or of Figs. 37 and 38 on Plate XI. of the Oceanic Ichthyology; 

 it has the following measurements : Total length, 15.5, head, 3.5, snout to vent, 

 G.5. and snout to mouth, 2.5 inches. The individual is an immature male, too 

 young to have acquired the frontal tenaculum, the ventral tenacula. or the 



