PART 1 GARTH : PACIFIC OXYRHYNCH A 415 



Breeding: A 21.9 mm ovigerous female from Maria Magdalena 

 Island, Mexico, has been found since the species was described. It was 

 obtained by the Velero III in May, and is smaller than the nonovigerous 

 female from Port Parker, Costa Rica, which, if perfect, would measure 

 well over 30 mm. 



Remarks: The slight differences noted in the original description 

 with respect to specimens from Port Parker, Costa Rica, and La Liber- 

 tad, Ecuador, now appear to be inconsequential and, but for their re- 

 moteness from the type locality, Isabel Island, Mexico, these specimens, 

 together with a 14.6 mm male from La Libertad collected by the Fred 

 E. Lewis ship Stranger, might well have been designated paratypes. 



Macrocoeloma heptacanthum (Bell) 



Pericera heptacantha Bell, 1835b, p. 173; 1836, p. 61, pi. 12, figs. 6, 



6r-u. A. Milne Edwards, 1873b, p. 55. Not White, 1847, p. 10. 

 Macrocoeloma heptacantha, Miers, 1886, pp. 79, 81. 

 Macrocoeloma heptacanthum, Rathbun, 1898, p. 576; 1925, p. 473, pi. 

 173, fig. 1 ; pi. 269, figs. 8-11, text-figs. 133, 134. 



Type: Male, originally deposited in the Museum of the Zoological 

 Society [London], and female, originally deposited in the Bell Museum, 

 cotypes ; neither type is extant. Length of measured cotype 36 mm, width 

 including spines 40.2 mm. 



Type locality: Puerto Portrero, Central America [Potrero Bay, 

 Costa Rica?], 13 fathoms; Hugh Cuming, collector. 



Localities subsequently reported, with collectors: Lower California, 

 Mexico: off Cape San Lucas, 31 fathoms, Albatross (Rathbun, 1898). 

 Panama: Panama Bay, 18 fathoms, Albatross (Rathbun, 1898). 



Atlantic analogue: Macrocoeloma septemspinosum (Stimpson). 



Diagnosis: Carapace with seven strong spines on its posterior half, 

 postlateral spine directed slightly backward. Rostral horns short, strongly 

 deflexed. Basal antennal spine pointing downward, not visible dorsally. 

 Male first pleopod undescribed. 



Description: Carapace suboblong, relatively wide behind the orbits 

 and narrow across the posterolateral angles [as compared to other species, 

 but still narrower anteriorly than posteriorly]. The seven spines of the 

 hinder half not very unequal, and five of them, the two pairs of bran- 

 chial spines and the cardiac spine, forming a nearly transverse line across 

 the carapace. Of the three median spines the gastric and the cardiac erect, 

 the intestinal spine curved and directed upward and a little backward. 



