THE TLUMULARID^E. 95 



than that of the latter, and the lower profile is often concave, while that of yl. apcrtn is usually 

 straight. When the gonosoine is present there is uo danger of confusing the two species, as they 

 are strikingly different in this respect. 



Type. In the Museum of Comparative Zoology, Cambridge, Massachusetts. 



AGLAOPHENIA APERTA, new species. 

 (Plate XX, figs. 1,2.) 



Trophosome. Colony unbranched, attaining a height of about 3 inches; stem not fascicled, 

 without pronounced interaodes, the processes bearing hydrocladia with a perforated protuberance 

 on each; hydrocladia alternate, divided into regular iuteruodes, each of which has a single incom- 

 plete internal septum opposite the intrathecal ridge. Hydrotheoe rather deep; anterior profile 

 moderately concave; margin with nine well-defined teeth; intrathecal ridge short, but evident; 

 supracalycine nematophores reaching to the level of the top of the hydrotheca; mesial neuia- 

 tophore with its distal portion projected nearly at a right angle with the hydrotheca, and its lower 

 profile straight; two cauline iiematophores on the front of each internode of the stem. 



Gonosoine. CorbuLc with about eight pairs of free leaves, each with two rows of nematophores 

 On its edges, and a rather strong process at its base; a long, narrow, transparent space is seen in 

 each leaf; the tops of the two leaves composing each "pair" meet in the central line above the 

 corbula and do not alternate so distinctly as in most species. 



Distribution. Albatross Station 2326, lat. N. 23 12', long. W. 82 19'; depth, 194 fathoms. 

 State University of Iowa Expedition, oft' Habana; depth, 200 fathoms. 



This species is readily distinguished by its long and prominently projecting mesial uematophore 

 in connection with the deep hydrotheca. It is nearest to A. apowtrpa, especially in the gonosoine, 

 which may be distinguished, however, by the fact that the corbnla leaves in aperta are more 

 nearly opposite than in aporarpa. 



Type slides. Cat. Xos. 18040, 18048, U.S.N.M.; Cat. Nbs. 15355. 15356, Mus. State Univ. Iowa; 

 also in the collection of the author. 



AGLAOPHENIA CRISTIFRONS, new species. 

 (Plate XX, figs. 3,4.) 



Trophosome. Colony unbranched, attaining a height of about 2 inches; stem not fascicled; 

 internodes obscurely indicated; hydrocladia alternate, rather distant, long, projecting at right 

 angles from the stem ; iuteruodes without decided internal thickenings. Hydrothec;e not closely 

 approximated, rather deep; anterior profile decidedly concave; margin with nine rather shallow 

 teeth; intrathecal ridge evident, oblique, and extending nearly halfway around the hydrotheca; 

 supracalycine nematophores slightly overtopping the hydrotheca'; mesial neinatophore rather 

 long, the distal end forming something less than aright angle with the axis of the hydrotheca; 

 aperture extending along the upper side nearly to the hydrotheca; lower side of neinatophore 

 slightly convex; cauline nematophores one at the base of each hydrocladium, and two others on 

 each internode of the stem. Color of stem dark brown. 



Gonosoine. Corbulse closed, robust, composed of five to seven pairs of broad leaves, each of 

 which bears a row of long and prominent iiematophores on its distal edge, and a blunt spine at its 

 base. There is a single hydrotheca between the corbula and the stem. 



Distribution. Albatross Station 2323, lat. 1ST. 23 11', long. W. 81' 19'; 1(53 fathoms. 



The trophosoine of this species is different from its allies in the fact that the somewhat distant 

 hydrocladia are given off at exactly a right angle with the stem. The gonosoine is qnitt distinct, 

 being much more robust and broad-leaved than its immediate relatives. The name 'rrixtifrons' 

 refers to the prominent crest of nematophores projecting forward from the distal end of the 

 corbula. 



Type slides. Cat. Xo. 18649, U.S.N.M.; Cat. Xo. 15357, Mus. State Univ. Iowa; also in the 

 collection of the author. 



