STERCORARIUS PARASITICUS, PARASITIC JAEGER. 611 



into the large anterior cavity, the cloaca proper, and the posterior dilatation is un- 

 usually well marked by a very prominent projecting ridge or fold of mucous mem- 

 brane. Just anterior to this ridge, ou either side, open the ureters, and in the male, 

 in close proximity to them, the orifices of the vasa deferentia. The papillte denotiuf 

 the terminations of these tubes, as well as the orifices themselves, are exceedingly 

 minute and require careful search for their discovery. The posteritw dilatation of the 

 cloacal parietes leads through a very narrow canal — a fourth of an inch or There- 

 about iu length — into a well- developed bursa. This pouch is quite capacious, measur- 

 ing nearly a third of an inch in length by a fourth in breadth. It is of a flattened 

 oval shape, with a rounded free extremity, and in situ lies pretty closely opposed to the 

 posterior wall of the cloaca. 



The superior larynx is small and very simple in structure, being, as usual, merely a 

 flattened conical cavity formed by the plane thyroid cartilage inferiorly, supporting'at 

 its auterior extremity the arytenoid cartilages which form the rima glottidis ou the 

 superior aspect of the larynx. This aperture is commauded by the ordinary con- 

 strictor and dilator muscles. 



The trachea measures five inches in length from the superior to the inferior larynx. 

 It is, as usual, flattened antero-posteriorly. The compression is more marked near the 

 anterior extremity ; the tube becomes more rouuded and narrower toward the lower 

 larynx. It is composed of about ninety rings. But few of these riugs are of uniform 

 width for the whole of their circumference. They are mostly broader at one point 

 than at another, the narrow part of one being opposite a correspondingly broadened 

 portion of the one next succeeding, so that the inequalities of any two rings mutuallv 

 correct each other. Along each side of the trachea a quite distinct baud of muscular 

 fibres runs the whole length of the tube. 



The cartilage composing the lower larynx is much firmer and denser than that of the 

 upper. The rings of which this portion of the air passage was origiually composed 

 are on its posterior aspect still distinctly traceable, but anteriorly the marks of sepa- 

 ration are quite lost, and the surface of the larynx is quite smooth. The shape of the 

 larynx is that of a truncated ijyramid, with a subtriangular base, whose posterior plane 

 has a concave indentation, and whose anterior edge has become obsolete. Above, the 

 o]5ening of the larynx is a simple flattened oval, similar iu shape to the trachea. Re- 

 low it is divided in two by a cartilaginous trabeculum, which is thrown across fmui 

 the posterior side to the anterior apex of the base of the pyramid. The shape of this 

 septum is such that it forms of the lower aperture of the larynx two oval openings — 

 the commencements of the two bronchi. 



The bronchi consist of about twenty half rings, their posterior parietes being en- 

 tirely membranous. These riugs are slender and of uniform width, the meiubraue 

 connecting them, and completing the canal posteriorly, being delicate and elastic. 

 They are of about e([ual length. 



Synonymy. — The account of Stercorarius striatus is one of the earliest aud an accurate 

 description of this species. The Larus crepulatuH of Gmelin aud Latham is in all prob- 

 ability based upon the young ; and, if so, lias of course priority over pomatorhinus. But 

 the description is short, unsatisfactory, and not diagnostic; while, being based upon 

 an immature state of plumage, which the Pomarine Jaeger shares with parasiticus, I do 

 not think it advisable to sui)ersede a long and well-known name. The Slcrcor<(rius 

 vrepidatus of Vieillot is, however, the true imrasiticits, as is also the Lcstris cnpidata of 

 Deglaud, and of Schinz; but the Lcstris crcpidata of Brelun refers to -S'. buffoui. ( Vide 

 synonyms of these two species.) The only instance I have found of the application of 

 the nnuw j)arasiiicus to this 8i)ecies is that of Meyer and Wolf. The rest of tlie synon- 

 ymy does not reixuire special notice. For a discussion of Catharacta cvpphus of Jiriiu- 

 uicb see remarks under S. buffoni. 



STERCOEAKIUS rARASITICUS, {Brilnv.) 



Parasitic Jaejjer. 



Lams parasitiem, LiXN., Fn. Suec. 55 ; Syst. Nat. i, 176G, 226.— Gm., Syst. Nat. i, 17-6, 

 f.Ol.— Lath., lud. Oru. ii, 1790, 819. 



Catharaila parasitica, 15i:unn., Oni. IJor. 17()4, '.V7. 



Cataracta parasitica, Kktz., Fn. Siu-c. 1800, l«iO. 



Cutarractes parasiticus, Flk.m., IJr. An. 138. 



Leatria parasitica, Ii.i.., Prod. 1811, 27:?.— Tkmm., Man. ii, 1820, 79(> (includes next spe- 

 cies).— Faukk, i'rod. Isl. Orn. 1822, 10.') (both si>ecies?).— J5<>ii;, Isis, l.-'22. .">C)2.— 

 Bkeiim, Eur. Viig. 182:5, 744.— Kai.I', Sk. Knt. Eur. Thierw. Is-J<i, 47.— Lkss., 

 Tr. Oru. 18:n, «il(i.— Sciiixz., Eur. Fu. i, 1S4(I, :5'J0.— Xaim., V. I), x. IslO. .'.10, 

 l)ls. 272, 27:{.— Bi'., Consp. ii, 1,^5(1,208; Conq.t. Kend. xlii, 18ot), 770.— Blas., 

 .F. f O. 18().'>. :{H4. 



Leatria parasitica var. coprvtiurea, Br., Consp. Av. ii, 18o(J, 209. 



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