. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EMBRYOS OF A MARINE CADDIS FLY 99 RESULTS Seasonal occurrence Embryos of Philanisus plebenis were obtained from starfisb hosts in every month of the year except the winter months of June and July, and the mid-summer month, January. The numbers of host starfish in each monthly sample of 30 individuals were as follows : January, 0 ; February, 6 ; March, 8 ; April, 2 ; May, 6; June, 0; July, 0; August, 2; September, 8; October, 8; November, 8; December, 1. In the majority of hosts, only one batch of eggs was found in each host
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EMBRYOS OF A MARINE CADDIS FLY 99 RESULTS Seasonal occurrence Embryos of Philanisus plebenis were obtained from starfisb hosts in every month of the year except the winter months of June and July, and the mid-summer month, January. The numbers of host starfish in each monthly sample of 30 individuals were as follows : January, 0 ; February, 6 ; March, 8 ; April, 2 ; May, 6; June, 0; July, 0; August, 2; September, 8; October, 8; November, 8; December, 1. In the majority of hosts, only one batch of eggs was found in each host individual. The eggs of a batch adhered loosely together and showed synchronous development, indicating that they had resulted from a single oviposition. The arm selected for oviposition was random, showing no fixed relationship with the madreporite and no discrimination of the sex of the host. In a few host individuals, two batches of eggs were found in different arms, one batch being advanced in development, the other early, clearly the result of separate ovipositions. None of the starfish examined were found to contain hatched, first instar larvae of Philanisus, although on several occasions hatching took place shortly after the host had been opened. The newly hatched larvae were very active and voracious, attacking the dissected host tissue. It seems likely that they eat their way out through the host body wall immediately after normal hatching. Embryonic development In each batch of eggs, 30-50 eggs are grouped together in short strings (Fig. 2), adhering loosely by chorionic contact. When transferred to sea water in a Petri dish, the individual eggs of a batch can be separated by light pressure with a fine dissecting 2mm. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marine Biological Labora
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
