Bulletin 47, United States National Museum, 



3 BUANt'HIOSTOMA CALIFORXIENSE.* Gill. 

 (Cai.ifounia Lancelet.) 

 Larger than the other American species, with the luu.scuhir bauds in 

 greater number, usually 44 + 16 + 9 — 69. Tail very short. Usual length 

 70 mm., or nearly 3 inches. Coast of California, from San Uiego Bay 

 southwanl, very abundant at the mouth of San Diego Bay, where it was 

 first obtained by Dr. J. G. Cooper about 1868 ; lately taken in large num- 

 bers at San Diego and at San Luis Gonzales Bay, in the Gulf of California. 

 In specimens from the last-named locality (Albatroso Coll.) the usual for- 

 mula is 45 -f 14 -I- 9 = 68. 



Branchio!<toma, spccios, Cooper, Cronise, Nat. Wealth California, 489, 1808, San Diego. 

 Branchiosloma caUforniensis, Gill, MS., Andrews, /. c, 241, 1893. 



2. ASYMMETRON, Andrews. 



7 Epigonichthys,-f Peters, Beii. Mouutsbcr., 327, 1876, (cultellus), 



Asymmetron, Andrews, Studies Biol. Lab. Johns Hopkins Univ., v, 237, 1S93, {lucaiiauum). 



Gonads, or reproductive structures, developed on the right side only. 

 Anal fin without fin rays or successive fin-ray chambers. A long caudal 

 process. Otherwise as in Branchiostoina. One species. («-aw/<erpof, 

 wanting symmetry.) 



4. ASYMMETRON LUCATANUM, Andrews. 

 (Bahama Lancelet. ) 

 Right metapleuron continuous with the median ventral (anal) fin, which 

 passes to the right of the anus. Preoral hood extensive, the cirri united 

 by the membrane throughout the greater part of their length, and smooth, 

 without sensory papilhe. Gonads on the right, 29, extending from the 

 15th to the 43d myotomes inclusive. Myotome formula 44 + 9 + 13 = 66. 

 Length i inch. Adult and young swimming at the surface in the evening 

 in June and July at Bernini and Nassau, Bahamas; also taken buried 

 in calcareous sand. (Andrews.) (Lucayas, the islands discovered by 

 Columbus in 1492, now the Bahamas.) 



Asijmmelron liwai/auinn, Andrews, I. c,237, 1893, Bemini, Bahamas. 



Class II. MARSIPOBRANCHII4 



(The Lampreys.) 



Skeleton cartilaginous ; the skull imperfectly developed, not separate 

 from the vertebral column. No true jaws, no limbs, no shoulder girdle, 



♦Closely allied to this species is B. elongalnm, Sundevall. Myocomniata 49 + 18 -|- 12 = 79. 

 Lonpth 13.^ to 23^ inches. Chinchas Islands, Peru, probably extending northward to Panama, 

 but nut yet recorded within our limits. (Sundevall, Olfcrs. Vet. Akad. Forh., 147, IS.W, 

 Chinchas Islands.) 



t Epifionichthys is said to differ from Branchiosloma in the absence of the anal fin. Dr. Andrews 

 states that Mr. Arthur Willey, who has examined its Australian type, E. cuUeUtis, finds gonads 

 on the right side only, as in Axiinimctron. If Ani/mmelroii is a valid genus, probably Epiiioitk-htlii/s 

 Is also valid. It is pnrhaiis distinguishable fron'i Asy>nme(ron by the want of a caudal process. " 



1 Prof. Cope niakcH the Mi(tvip<ihrnnchiia.e\ihc\iws under a class Ai/natlia, characterized by the 

 absence of jaws and shoulder girdle. This class is composed chiel'lv of extinct forms, most of 

 .thorn belonging to the subclass Ostmcodermi, and provided with bony dermal plates and lateral 

 limbs. See American Naturalist, October, 1889, 863. The group MarsijtohranvhU is nUo often 

 known iw Cyclostomi, as Dcrmopteri, and as Myzonles. 



