SCYLLIID^E. 311 



therefore, lasts about nine months."' The late Professor Peters, writing to me 

 from Berlin, observed (November 11th, 1881) that " in our aquarium Dr. Harmer 

 has noted the day of the laying of the eggs and their opening. This varies from 

 156 to 18t) clays." In adult females ova may be observed in different stages of 

 growth, and generally passing down the oviducts in pairs, or one in each oviduct 

 becoming there enclosed in a horny covering. Mr. Jackson observes that "at the 

 Sonthport Aquarium they take from seven to ten months to hatch, and the young 

 fish is never visible until several months after the eggs have been laid. The first 

 appearance of the egg- case is of four long tendrils hanging from the body of 

 the female ; she herself will be found wriggling round and round any suitable 

 object, until she has secui^ely attached these tendrils. She then draws the two eggs 

 (I have always seen two laid at once) from her body, and the few remaining 

 tendrils soon get attached also." Mr. Dunn sent me from Mevagissey a beautiful 

 specimen of flexible coral, Oorgonia, to which the egg of one of these fishes is 

 attached. Couch also has observed the same occurring off PolpeiTO. 



These egg-cases or pixy purses possess slits, which Owen considered admitted 

 streams of water into the egg at these openings, and that the cloacal apertures 

 of the uteri would seem adapted to allow the free ingress of sea- water and that 

 the external temporary branchiae of the embryo may perform the respiratory 

 function. Couch has observed that the presence of even a small quantity of sea- 

 water at an early stage is fatal to their life. In October, 1881, Mr. Hearder dispatched 

 to me by post from Plymouth one of these egg-cases with the young an inch long 

 within, and it arrived on the 29th in a very lively condition. It had been placed 

 in a wide glass tube 3| inches long by 1 inch in diameter, and secured at both 

 ends. The egg-case was sufficiently transparent to enable one to see what was 

 going on within, it contained a long oval cavity slightly constricted near its 

 inferior third ; below this constriction was the nutrient vesicle, which was thus 

 prevented from passing forwards into the anterior part of the chamber where the 

 embryo was. The interior of the chamber was filled with a yellowish- white thud, 

 and here the young was in almost constant motion, as if its main object were 

 to agitate the contained fluid. Under the microscope the motion of the blood 

 through the vessels was plainly perceptible, loops passed out from each of the 

 gill-openings as well as from the spiracle, and along them the course of the red 

 blood corpuscles could be clearly traced, as well as through the heart and large 

 vessels of the body. After the death of the embryo I cut the egg-case across and 

 could not discover that the slits were yet pervious. Where these slits exist 

 they may be for the purpose of more readily admitting oxygen to the contained 

 fluid. 



Mr. Jackson, at Southport, kindly made some investigations into this question, 

 and came to the conclusion that the slits are open from a very early age but 

 difficult to see. He obtained one of the eggs of this fish, about as much developed 

 as the one I have described, this w r as carefully dried and oiled all over except the 

 slits ; after eighteen hours no effect had been produced. He then dipped the ends 

 in oil, and twenty-four hours after the fish was all right. The oil appealed to 

 have dissolved whatever holds the ends together, for on lifting the egg-case a 

 good deal of liquor escaped. The whole was then immersed in oil,, and for nearly 

 three hours little effect was produced, but then the oil appeared to have dissolved 

 the ends sufficiently to make its way inside the case, and the young fish was thus 

 drowned. On further examining live specimens at an early age, Mr. Jackson 

 remarked that when lifting the egg-case out of the water the slits were so large 

 thai the fluid escaped, and on returning the case into the water it was found to be 

 half-full of air. Possibly the period at which the slits first become pervious is 

 subject to variation. 



Uses. — Of little value either as food or for oil. Are employed on the Irish 

 coast as bait in " buckie " creels to capture shell-fish, Buccinum undatum, 

 and crabs. At Rathlin are said to be valued for their oil. Parnell remarks 

 that the skin of this and other species of sharks are used as a substitute 

 for glass paper, and by turners for polishing wood. 



A$ food. — Said to be eaten by the poor at Roundstone, in Ireland, and other 



