A REVIEW OF THE MYSIDACEA 165 



A point of morphological interest, first observed by Zimmer (1927) , 

 may be referred to here. The brood pouch is composed of two pairs 

 of brood lamellae attached to the seventh and eighth thoracic limbs as 

 outgrowths from the coxal joints of the endopods. On the inner mar- 

 gins of the coxal joints of the endopods of the fifth and sixth thoracic 

 limbs (fig. 65) of the female there is a small expanded setose lobe 

 projecting inward and lying against the sternum of the thorax. The 

 position of these lobes and their morphological relationships suggest 

 that they represent vestigial brood lamellae, which no longer function 

 in that capacity. Their relatively strong setose furnishings likewise 

 suggest that they have taken on a new function, which is probably that 

 of baling organs to help to maintain a steady flow of water through 

 the marsupium. This current probably flows from behind forward 

 through the marsupial pouch and helps to supplement the aeration 

 of the water in the pouch by the pulsating movements of the large 

 brood lamellae. There is no trace of the median sternal processes 

 which I recorded as present in the marsupium of Neomysis rayii and 

 allied species (Tattersall, 1932b), or of the baling lobe on the anterior 

 pair of brood lamellae present in the latter species. 



I counted the embryos in the marsupium of a large breeding female 

 of M. stenolepis measuring 28 mm. in length and found that they num- 

 bered 190. This fact will emphasize the remarkable potential breed- 

 ing capacity of this species. I am unable to give corresponding figures 

 for M. mixta because of the absence of large breeding females in the 

 material examined by me. 



MYSIS OCULATA (Fabricius) 

 FIGURE 61 



Cancer oculatus Fabricius, 1780, p. 245. 



Mysis flexuosus Adams, 1852, p. ccv. — Walker, 1862, p. 68. 



My sis fabricii Bell, 1855, p. 404. 



Mysis spinulosus Packard, 1863, p. 419. 



Mysis oculata Stimpson, 1863, p. 2. — Packard, 1867, p. 301. — Smith, 1883, p. 221 ; 

 1885, p. 57.— Dawson, 1886, p. 202.— Fewkes, 1888, p. 49, pi. 2, figs. 5, 6.— 

 Ohlin, 1895b, p. 8— Aurivtllius, 1896, p. 212.— Ortmann, 1901, p. 160.— 

 Stafford, 1912, p. 60. — Kindle and Whittaker, 1918, p. 252. — W. L. 

 Schmitt, 1919, p. 4b. 



Occurrence. — North Atlantic: U. S. Fish Commission Grampus 

 station 42, September 21, 1 male, 5 females ; 9 miles off Webster Point, 

 N. Y., Oct. 14, 1894, C. H. Stronger collector, 12 specimens from 

 stomach of bloater from deep water; Indian Harbor, Labrador, Au- 

 gust 12, 1908, Owen Bryant collector, 16 immature specimens. 13 



M These specimens -were sent to me in exchange as M. relicta, but I believe them to be 

 young specimens of M. oculata. They were identified by Dr. Mary J. Rathbun, and they 

 are probably those recorded in 1909 in Grenfell, "Labrador : The Country and Its People." 



