DEPARTMENT OF MARINE BIOLOGY. 201 



recorded from the Torres Strait region. We collected at Maer alone 151 

 species and at Thursday Island and Badu 26 others, not taken at Maer. Of 

 the 117 species previously known, we found only 42, so that there are now 

 known from this limited area not fewer than 250 species of echinoderms. In 

 our collections there appear to be at least 45 species not previously known to 

 science. There is abundant evidence that this extraordinarily rich fauna is 

 not by any means yet fully known. We were so unfortunate as to lose our 

 dredge after a single haul, and although we made several attempts to use a 

 tangle, and on one occasion had a Japanese diver working in 18 fathoms, the 

 results were meager. Our collections are therefore exclusively littoral in a 

 very narrow sense. Dredging in deeper water will certainly reveal additional 

 species. But not even the very littoral fauna is fully known. It is an actual 

 fact that every day on the reef at Maer revealed species of echinoderms not 

 previously seen, and on the last day at the island, after five weeks of con- 

 tinuous search, no fewer than four species were found which had not been 

 noted before ! These facts furnish abundant evidence that the littoral echino- 

 derm fauna of Maer is extraordinarily rich, very possibly one of the richest 

 in the world. 



Thanks to the kind foresight of Dr. Mayer, Mr. E. M. Grosse, of S3^dney, 

 accompanied us to Torres Strait as artist, and devoted his time exclusively 

 to the making of colored drawings, from life, of the more interesting echino- 

 derms. It would be difficult to exaggerate the success of Mr. Grosse's work. 

 No artist could have been more interested, willing, and industrious than he, 

 while more than 100 beautiful figures furnish abundant evidence of his skill. 

 It was a remarkable piece of good fortune to secure the services of such a man. 

 The figures will be used in the illustration of a complete report on the echino- 

 derms of Torres Strait. 



I desire to express my gratitude to the authorities of the Museum of Com- 

 parative Zoology for granting me the necessary leave of absence for so long 

 an excursion, and to Mr. Etheridge, Curator of the Australian Museum, 

 Sydney, for much assistance, without which I should have been seriously 

 handicapped. 



The Habits of Astroscopus and the Development of its Electric Organs, 



hy Ulric Dahlgren. 



Strong efforts have been made by the writer for the last 5 years to secure 

 suitable embryonic and larval stages of the fish Astroscopus in order to study 

 the origin and development of the peculiar electric organ found under each 

 eye. The fish is considered rare by naturalists, but continuous work in the 

 neighborhood of Norfolk, Virginia, on its habits and the methods of its cap- 

 ture, indicate that it is not as rare as was thought. Over 200 specimens, 

 ranging from 3| inches to 21 inches in length, were secured in one season of 

 about 8 months. 



When the necessity of securing embryos became apparent, a special study 

 of breeding habits, etc., was undertaken. A clew to the breeding habits and 

 early development of the fish was sought by comparison with some of its 

 nearly related forms. The habits of Opsanus and Porichthys are well known; 

 both lay a few large eggs in "nests" of various kinds, and these eggs devel- 

 oped slowly into large embryos. No help was forthcoming here, and it was 

 feared that perhaps a nest was made deep in the sand and in deep water, where 

 the young would be nearly inaccessible. A study was then made of the ovaries 

 and testes of large fishes at various times of the j^ear. At first only fish from 

 inside Chesapeake Bay were examined. These ran up to as long as 13 inches 



