OCEANIC ICHTHYOLOGY 



BASED UPON A STUDY OF 



THE DEEP-SEA FISHES OF THE ATLANTIC BASIN, 



By George Brown Goode and Tarleton H. Bean. 



A DISCUSSION OF THE SPECIES AND THEIR DISTRIBUTION. 



Class MARSIPOBRANCHIL 



Marsipohranchii, BoxArARTK, Trans. Linn. Soc. Loiulou, v. 18, pp. 2S9, 304, 1841. 

 MamqiiihrnncliUi , Gli.i., .loliDsou's Cydopn>di;i, iii, 31tj. 

 Dermojileri (part), OwiiN, Auatumy of Vertebrates, I, 7. 



Skeletou of a very inferior type, the notocliord or embryonal vertebral column being- 

 persistent. Skull rudimentary and represented by a small brain case and capsules for 

 the organs of sense (auditory and olfactory), as well as by an ethmovomerine plate; the 

 inferior appendages developed as elements designated as the "subocular arch," with a 

 metapterygoid or "superior quadrate" and an "inferior (piadrate" portion, the "palato 

 pterygoid" element, and the "stylohyal process;" labial cartilages form also a prominent 

 feature of the skull; bones or cartilages, representing the upper as well as the lower jaws, 

 entirely wanting; the branchial apparatus sustained by a basket like skeleton; no limbs 

 developed, and no scapular arch or pelvic girdle. Brain small but distinctly developed, 

 differentiated into the brain proper and medulla oblongata; the former comi^osed, as in the 

 higher forms, of the " mesencephalon," " thalainencephalon," "prosencephalon," and " rhiuen- 

 cephalon;" the latter small, with a fourth ventricle conspicuous fi'om above, and the "cere- 

 bellum" very rudimentary. Auditory apparatus quite simple, represented by a single mem- 

 branous tube without any differentiation into canals and vestibules, as in the Hyperotreta, 

 or, at most, as in the Hyperoartia, with two semicular canals and a sacculated vestibule. 

 Olfactory apparatus consists of a median sac; is provided with but a single external aper- 

 ture. Heart distinctly develo])ed and divided into an auricle and ventricle, the former hav- 

 ing in front a venous sinus, and the whole inclosed in a "i)ericardiuni," wliich connects with 

 the peritoneal cavity. Intestinal canal simple; liver specialized as such, and kidneys well 

 developed, with ureters opening behind into the rectum. Organs of generation without 

 ducts, discharging into the abdomen, from which the products depart by an abdominal pore. 

 The species of the class are found iu both fresh and salt waters, the Petromyzoutids 

 having members in the fresh and salt waters of all temperate and subtemperate countries; 

 while the Myxinoids are represented in tlie cold waters of the northern hemisphere by 

 ^f!/.l■!ne, as well as along the shores of a considerable portion of the Pacific — in the 

 Japanese and Chinese seas, California, Chile, and Australia. 



19868— No. 2 1 1 



